I went with the Back Flip. A three panel fold up. I like it so far. Easy to use. Will come completely off if you want it to with no hasle. My deeler recomended it over the more expensive roll ups for durabilty sake. No moving parts like springs, cables ect. I like that. It is NOT waterproof. I don't think any of them are. They call it 95% waterproof. It is very secure with no aditional locks to deal with. You cant open it unless the tailgait is down. Also, I do recomend getting the real Back Flip brand. There is cheap imatations. I can't see them holding up as well.
I spend a lot of time off road. I haul a lot of sensitive and expensive equipment in the bed. Once you put a cover on a Trail Boss bed you will quickly discover there is a 1/4" gap around three sides of the tailgate and the bed. When your on dirt trails the venturi effect kicks in and sucks dirt into your covered bed like a shop vac filled it up! Easy fix. I put 3/8" adhesive weather stripping all the way around on the bed side to form a seat for the tailgate to mate to. All is well now.
Kind Regards,
Steve